An Introduction to UID

The IUID program of the DoD has introduced the UID marking system for the DoD items for enhanced management of the items. The UID is a globally unique identifier of the item that makes the particular item distinguished from all other items. There are some distinct criteria for the UID marking and the items or parts that qualify the requirements must be assigned with a unique identification. The contractors or the suppliers are generally responsible for marking the items with UID.

What is UID?

UID is a 2 dimensional data matrix barcode that is either engraved directly on the surface of the item or marked on UID labels or nameplates that are affixed to the item. As the UID simplifies the item management and the item tracking process of the DoD, it is required that the marking should be permanent for the life of the item. As the IUID program is a foundation to the item visibility across all the departments of DoD, improved life cycle item management, they need to be marked with correct format and correct data.

The DoD requires that the contractors must select the UID marking methods depending on the requirements and the item that are being marked. As the data elements are entered in the 2D data matrix barcode format, it also requires a barcode reader to get identified. The most important is, the contractors or suppliers need to follow the instructions stated by the DoD while marking the items to meet the DoD standard.

The MIL-STD-129 Standard For Marking of Shipment

The MIL specs for different items differ depending on the nature of the items. The MIL-STD-129 standards are set of instructions aimed at achieving standard objectives.

MIL-STD-129 is one of the DoD MIL specification standards. This fundamental military standard is meant to maintain uniformity in the military product marking for shipment and storage. It is essential that all military equipments and ammunitions supplied to DoD through shipment should be marked according to standard and specifications mentioned in MIL-STD-129. As any MIL specs, used by DoD to achieve standardized objectives, the MIL-STD-129 is specifically designed for the shipment and storage. The standard mentions the details of marking the items beginning from designing and construction to quality control and maintenance. The MIL-STD-129 has provided separate instruction for tagging, marking and labeling.

The DoD MIL specs keep on changing in regular interval of time keeping in mind the necessary requirements. For instance, the DoD observed certain drawbacks in the marking system according to the MIL-STD-129 standard. As the container marking bears same level of significance as the item marking, the discrepancies in the standard was rectified with the upgraded version of MIL-STD-129, ie. MIL-STD-129P. The revised version of MIL-STD-129 was introduced on 16^th January 2006. Although the MIL-STD-129 standard is a rigorous practice for item marking, the contractors are required to follow the instruction regarding application of numbers, labels, tags along with use of symbols and colors.

The specifications requirements for different kinds of containers are discussed bellow.

Unit Containers

The containers are listed only after they are assigned with unique serial number by the Government or the manufacturer for identification or control. The MIL-STD-129 standard has also mandated that the serial number should be entered in a clear format. The other data required for marking the Unit Containers are National Stock Number (NSN) Barcode, NSN,CAGE, part number, quantity, item description, unit of issue, contract number, date of preservation, lot number (if used), method of preservation code. Shelf marking of the containers is required to specify the start of shelf life of the items that need to be tested or disposed of.

It is to remember that the serial numbers assigned to indicate the quantity produced should not be listed. Sometimes, the exterior containers are used as unit containers, and at that time the exterior container rules are applied for the unit container.

Intermediate container

The rules for marking the intermediate containers are the same as the unit container and the same data are applied except the serial number. When an intermediate container contains more than five serial-numbered items, the exterior container rules for the serial number are applied for the purpose.

Exterior Container

For the exterior container, the basic rules of the unit container are applied except some of the specific identification marking requirements. The MIL-STD-129 specifications, there are few exceptions in the marking procedure. For instance, it is mandatory that the Contract Number, NSN, and CAGE Code should be entered in the barcode format. The marking of exterior container doesn’t require item descriptions. The additional levels required for the marking are Military Shipment Label (MSL), Direct-Vendor Delivery (DVD) Label, Serial Number Barcode(s).

The MIL-STD-129 specifications are crucial part of DoD’s item tracking process.

Direct Part Marking and Its Diverse Benefits

Direct part marking or DPM is one of the two methods of marking the DoD items with unique identification symbols. It is the technology of applying machine readable 2D data matrix barcodes directly to the surfaces of the parts and items.

The marking process is essential for automate the information retrieval process. Basically, the technique enhances permanent unique part identification and improves quality. The Direct part marking process is also useful to reduce errors, reduce the life-cycle cost and improve readiness. Data matrix is the standard for direct part marking.

Direct part marking has the same functionality required for unique identification marking. The DoD function of documentation and databases that are essential for keeping track of the processes such as manufacturing, procurement, shipment, installation and storage are performed with the marking system. The DPM also allows identifying items during storage, handling, functional use, installation, repair, replacement and maintenance.

Application of Direct Part Marking

The DPM is applied to items considering certain conditions such as metal of the parts, thickness of the surfaces, texture of the surface, etc. First of all direct part marking is applied considering the function of the parts for safety critical operation. The shape of the part is important to consider before applying the DPM process of marking. For instance, it is difficult to etch the data elements of the UII on a curved surface. On the other hand, a flat surface makes convenient environment for such marking procedure.

The surface type ad texture of the item influences the direct part marking process. It is difficult to apply different methods of DPM on a polished surface. The environment in which the items are used and the functional life time of the items is essential to consider while directly marking an item. Metal of the item also determines the method of DPM that should be applied to an item. For instance, the chemical etching method can’t be used on all metals as it may affect the functionality of the product.

Although, the marking depth of the direct part marking should not exceed 1/10 of the thickness of the part, it is important to take proper care of the item thickness before selecting the exact direct part marking procedure.

Requirements of Direct Part Marking

The data entered through direct part marking remains readable throughout product life. As durability of marking is the prime aspect of applying item identification, permanent marking of the items can be achieved through this marking method.

As direct part marking considers several aspects, the marking methods ensures that the marking can withstand all environmental conditions that the product will be exposed to under normal operation.

Each marking methods are applied after testing the material of the items and their functional environment. Hence, direct part marking reduces the chance of any harmful effects on the functionality, reliability, or durability of the product.

Benefits of Direct Part Marking

• Reduce program costs
• Eliminate data transposition errors
• Improve data accuracy
• Provide means to verify part configuration and status prior to installation, repair, and overhaul
• Real-time computer system update
• Reduce inventory
• Track the history and quality of parts

The Marking Guidelines According to MIL-STD-129

There are different marking standards mentioned by the DoD. MIL-STD-129 is the standard mentioned to maintain the uniformity of marking of the military equipments.

The United States Department of Defense has made it essential that the items must be marked with unique identification for their ease management. The marking of the items with their UID helps the military personnel in the item tracking procedures. DoD has mandated a standard of the marking- MIL-STD-129- which has been approved by the DoD and other Government agencies. As the suppliers of the military equipments are required to maintain uniformity while marking and supplying military equipments, the MIL-STD 129 has set a standard for the suppliers. The suppliers are required to follow the instructions provided by the instructions to meet the UID standards and requirements while transporting the items.

The marking helps tracking the items when the stock goes short of balance level. However, the MIL-STD-129 requirement standard ahs categorized the container into three types such as Unit containers, Intermediate containers and Exterior containers. For all types of container, the basic formats such as national stock number (NSN), item description, and part number are mandatory. But there are certain changes in the marking of different types of containers.

Unit Containers – The Unit containers should be marked with the following data

• National Stock Number (NSN) Barcode
• CAGE, NSN, part number, item description, unit of issue, quantity, contract number, lot number (if used), date of preservation, method of preservation code, should be listed in clear and plain text.
• The unit containers are also marked with Shelf Life Markings that specify the start of shelf life along with the date an item needs to be tested or disposed of. Only the deteriorative items require Shelf life markings as specified by the contract requirement preparation for delivery Special Markings.
• The MIL-STD-129 requires that the serial numbers of each item in the container must appear in the clear and unambiguous barcode format. Serial numbers are listed only when assigned by the Government or the manufacturer for identification or control. However, the numbers are not listed when assigned by the manufacturer solely for indicating the quantity produced.

When the exterior container serves as the unit container, the exterior container rules apply.

Intermediate Containers

The intermediate containers are marked with the same data as unit containers, except the serial number. When there are more than five serial-numbered items in an intermediate container, the serial number rules for the exterior containers are applied.

Exterior Containers

The basic label format of the unit containers are used for the exterior containers as well. However, the item description is excluded from the format. The contact number, NSN, and CAGE Code must be entered in the bar code format. The marking is done by using one large label or placing two smaller labels side by side. The additional labels that the exterior containers may require are serial number barcodes, military shipment labels, direct vendor delivery label.

Following the standards of MIL-STD-129 may be a difficult task for the suppliers. However, depending on the situations, the requirements can be reduced to few basic sets of rules and labels.

Factors Influencing Direct Part Marking Methods

There are different types of direct part marking. But the marking methods are selected depending on several factors associated with the item or the part.

The Department of Defense has allowed two types UID marking of the items- direct part marking and application of UID labels. Direct part marking involves marking the item with a globally unique identification on the item itself. It is the process of marking a part with barcode symbols to allow tracking of the part or item for their full life cycle. When it comes to permanent marking of the items, the DoD specifies that the UID marking of the item should be permanent for the functional life time of the item which may vary from several months to several years.

Basically, industries such as aerospace, automotive and electronic manufacturers prefer direct part marking for reliable identification of the parts and items. As the DoD requires physical mark of UID on the tangible assets, the DPM assures safety and warranty along with satisfying the regulatory requirements. The 2D data matrix code is the most preferred bar code type for the barcode symbols that are used for the direct part marking of the items. However, some companies prefer QR Code according to their requirement. The UID marking method enables management and tracking of the items ranging in their value and sizes.

The various marking methods of direct part marking are Abrasive blasting, adhesive dispensing, Cast, forge or mold, Dot peen, Electro-chemical etching, Embroidery, Engraving/milling, Laser marking, LaserShot peeing, Lique metal jet, Stencil. There are other marking methods such as embossing, vibro-etch and manual metal stamp, but they are not for applying machine readable micro-size symbols.

How the Direct Part Marking Methods are Selected for the Items

There are number of different factors basing on which it is decided whether direct part marking is suitable for the particular item.

Function of the Parts

For the parts that are used for safety critical applications such as high stress system, or aircraft engine, the non-intrusive marking methods are used.

Geometry of the Part or the Item

The direct part marking is difficult if the shape of the item or the part is not convenient for the marking. It is difficult to etch the data matrix code on a curved surface.

Surface type

The direct part marking is difficult when the texture of the part surface is highly polished. The marking requires reducing the glare of the surface before marking.

Size of the Part

Though size of the parts is not a very important factor for using 2D data matrix code, the sizes of the texts are adjusted according to the available space.

Life Span of the Items and their Operating Environment

While selecting the method of direct part marking, it is essential to consider the functional life span of the items and the environment in which the items are used. It is important that the marking should be permanent.

Thickness of the Surface

It is essential to consider the thickness of the surface as there are chances of deformation of the part if the intrusive marking methods are used. The marking depth in most of the methods should not exceed 1/10 of the thickness of the part.

MIL-STD-130 N: The Standard for UID Marking

The MIL-STD-130 N is a necessary standard for defining the requirements for item identification. The scope of the MIL-STD-130 N includes describing both criteria and the methods used.

MIL-STD-130 N is a standard which has been brought forth and recognized by the Department of Defense and all its related Departments and Agencies. Clarification regarding the implementation of Machine Readable Information (MRI) is provided by MIL-STD-130 N. MRI is done for automatic data capture and item identification marking. MRI also provides a vital device for life cycle asset management. The process involves acquiring, manufacturing, defining the logistics and then disposing off the task.

MRI Is Not Enough

The MIL-STD-130 N however does not stipulate that all item identification should be done by MRI. There are some items which can be identified by Human Readable Information (HRI). It is important to identify which items are to be marked by MRI and which by HRI. A combination of both may be the answer for some items. MIL-STD-130 N stipulates that instead of MRI, free text information item identification can also be done.

Criteria For Marking

Product designers find out ways for better item identification marking requirements. The different criteria, on the basis of which this is done is laid down in the MIL-STD-130 N. While deciding the product definition data, the product designers must be specific about the requirements for marking content, application process, location, size and also the relevant marking materials for the process preceding the delivery of an article. It is not enough for the product designers to state that the marking is to be done according to MIL-STD-130 N standards. It will be difficult to design, develop and manufacture an item based on such little information. It will also be confusing to produce and procure the replenishment spare items.

The same applies for acquiring activities. They must also apply the MIL-STD-130 N in all their contractual instruments. As with product designers, they have to also lay down the requirements for item identification marking. Only a reference to MIL-STD-130 N standard is not enough. It has to be specifically stated that item identification marking is necessary and the criteria for developing the requirements must also be outlined.

To Define Without Conflict

Certain engineering documentation terminology is used by the product designer. The definitions laid down in the MIL-STD-130 N are almost in accordance with these terminologies. But irregularities are bound to occur. There might be discrepancy between the definitions followed by the product designer and the Automatic Identification Technology disciplines. There is ample provision in the MIL-STD-130 N to sort out such conflicts. There is also scope to cite the source in case of discrepancy.

Defining the Scope

So we can conclude that the MIL-STD-130 N is basically a standard for identifying the items belonging to the military and audited by the Department of Defense. This standard defines the criteria for the necessity of item marking requirements and also the methods for identifying these items. Both criteria and data content are issues addressed by the MIL-STD-130 N relating to free text and MRI for item identification marking. But while going through the standard, the figures should not be given much relevance. They are just there for the purpose of illustrations.

IUID: The Enhanced Item Traceability Program

The IUID program has introduced the marking of unique identification for the personal property of the government for better asset management and item tracking procedure.

The Unique identification (UID) program was launched by the Department of Defense in 2003 to simplify the item tracking process under the DoD. The UID program is associated with tracking, personal property, Government property and property under the possession of the contractors. IUID or the item unique identification program is a subset of UID and it aims at the personal property of the DoD. The prime goal of the IUID is to enhance the item management and tracking of the delivered items to the DoD by marking unique item identifier.

The IUID program ensures that the items are marked with globally unique identification. The UII, according to DoD, is “identifies an item with a set of data that is globally unique and unambiguous.” All the goods delivered to the DoD should be marked with UII by the contractors. The UII is a set of data that is encoded into 2D data matrix barcode symbols. The MIL-STD-130 has provided the instructions for the data and the manufacture of UID nameplates. The contractors are required to follow the instructions and construct the UID nameplates so that they meet the standard and the requirements.

IUID marking methodology is a business critical operation and the DoD contractors need to know it’s basic so as to get their UID marked items accepted by the UID Registry. In fact, the suppliers should understand the IUID marking program that enhances item traceability, asset visibility, and lifecycle item management and accountability. If the service provider of UII marking understands the capabilities of different marking methods, it is not too difficult or expensive to achieve IUID program compliance. The DoD only requires a permanent marking solution to the items with the help of the contractors.

2D Data Matrix Marking

While developing the IUID marking system, the most important consideration is to determine the most effective way of marking the items and applying the 2D data matrix symbols. The UII data are expressed in a 2D data matrix barcode symbols. The UID marking standard has specified the exact size and font type of the symbols and the supply should ensure that the symbols are in accordance with the standard before making it to UID Registry. Many contractors outsource the IUID marking to the subcontractors. However, it is the responsibility of the contractors to check the quality of marking.

The IUID marking program allows two important methods of marking- Direct part marking and application of UID labels.

Direct Part Marking

The direct part marking allows etching the symbols directly to the items or parts. However, the process is allowed considering the structural tolerance and composition of the item. The advantage of the marking is that it is a durable and one step process. However, the downside is if the data is entered incorrectly the item is wasted.

UID Labels

This is the ultimate IUID marking solution of the items under the DoD. They are constructed with metallic and non-metallic materials and affixed to the items with fasteners such as rivets and screws.

How to Connect the 2D Data Matrix Scanner

The advanced technology of connectivity is allowing better connection option for the 2D data matrix scanner. However, the options are selected according to the mechanism of the devices.

The UII marking of items are the efficient item management process of Government and private organizations. The UID data is engraved on the item or labels in the form of 2D data matrix symbols. The symbols are machine-readable codes and need to be decoded with a 2D data matrix scanner. The 2D data matrix scanner is an electronic device meant to interpret the printed barcodes on the items. Technologically, the device is developed with decoder circuitry that analyses the image data of the barcode and sends the interpreted data to the output port of the scanner.

Use of 2D data matrix scanner became widespread due to the use of 2D barcode symbols in the UII of the items. There are different methods of connection of the device depending on the usage.

Earlier, the barcode scanners of all formats used RS232 serial interface. The simple and electrical means of connection use easy and simple software, it needs to be written for particular computers and their serial ports though.

Proprietary interfaces are less common interfaces and were used with dedicated hardware. Wand emulation is another kind of output that decodes the raw wave. It can also convert the unrecognized symbologies into another kind of symbology that is easily recognized by the host device.

With the advent of innovative technologies, PCs has become the popular device. PCs and its standard keyboard interfaces are becoming convenient for any kind of user as they are easier to connect with physical hardware. With the commercial and general demand of reducing the complications of the associated software the ‘Keyboard Wedges’ have been introduced for connecting the 2D data matrix scanner. The ‘Keyboard Wedges’ is a hardware with characters from the barcode scanner appearing as if typed in through the keyboard and is attached between PC and its keyboard. This type of connection of the 2D data matrix scanner has simplified the use of the device. However, it has limitations in handling the content of the data matrix code.

Of course, these days, the USB connectors have replaced the keyboard ports for it is a more convenient hardware option. The easy integration of the scanner is retained by using a ‘software wedge’ in place of ‘keyboard wedge’.

PS/2 or USB cables are the becoming popular these days for connecting barcode scanners. The cables are connected with the 2D data matrix scanner at one end and the PS/2 keyboard port with another end. The data matrix codes are received by the host computer and converted keyboard input. Many scanner support the USB. Choices for the USB interface types are provided by many scanners. For instance, some of the devices have powered USB.

These days, most of the devices are being connected with wireless networking. The modern 2D data matrix scanners are also available with such facilities. The wireless enabled scanners are operated with the help of Bluetooth and WLAN. However, such devices use battery or rechargeable battery for their function which limit their time of operation.

With the changing technology the methods of connection of the 2D data matrix scanner is improving and being more user friendly.

The Compliance of DoD UID Labels According to the MIL-STD-130 N Requirements

The DoD UID labels are required to be according to the standards of MIL-STD-130 N. The mentioned criteria must be followed by the contractors to avoid rejection.

The DoD UID labels are one of the ways of marking the DoD items with unique identification so as to enhance their traceability. The Department of Defense has mandated that the labels should be MIL-STD-130 N compliant so that all markings of the items should maintain a standard. As the marking and serialization process of the items are the essential aspect of item management and tracking, the UID marking that doesn’t comply with the standards are rejected by the department. The DoD UID labels are marked with 2D Data matrix codes that are machine readable either by direct part marking or by applying permanent UID labels.

Apart from the feature that the unit acquisition cost of the items should be more than $5000, the other criteria that enables the items to have unique identification are

• The items are controlled inventory
• Serially managed
• Mission essential
• The item is customable where permanent identification is necessary.

As the basic identification marking standard of the DoD UID labels are regulated by the MIL-STD-130 N, it is mandatory for the contractors to obey the instructions provided in the standard. The standard has issued some specifications for the marking requirements and the marking methods of the UID.

Depending on the requirement of the UID marking of the item, the labels (nameplates, ID plates or Data plates) can be constructed with either metallic or non-metallic materials.

The DoD UID labels of the items are made of material either same or different that that of the material of the item. It is essential that the material of the labels shouldn’t cause any damage to the items and should get affixed to the material of the items or parts.

The standard has limited the number of characters of the UID marking of the labels to 50.

The criteria for machine-readable and human readable information of the UID data on the DoD UID label are declared by the MIL-STD-130 N.

The validation and verification of data are mandatory for each submitted data.

The warranty of contract between the government and the contractors states about the nature, utility and condition of the objects.

The drawbacks of the MIL-STD-130 have been rectifying for the convenience of the contractors and better management of the UID items. The latest version of the MIL-STD-130 N, which was released on December 17 2007, has mentioned the criteria for DoD UID labels, validation and verification. According to the standard, different lighting methods should be used for the different part marking. The contractors are required to follow the instructions provided for marking of UID and manufacturing UID labels.

The DoD UID labels are verified according to the cell modulation, cell size, cell contrast, print growth, reference decode, fixed pattern damage, unused error correction, axial non-uniformity, minimum reflectance, and grid non-uniformity. When the outsourcing of UID is considered, the DoD should ensure that the service should follow all the steps mandated by the standard. Even, the DoD UID label generating software must comply with the standards of MIL-STD-130 N.

Crucial Aspects of UID Nameplates

UID nameplates should meet the standard of the MIL-STD-130. There are various criteria mentioned in the standard for the marking of the nameplates.

Generally, UID nameplates and the labels are used with the items where the direct part marking is not suitable. Unique item identifier is mandatory for the DoD items for it has become a part of their item management process. However, there are certain criteria for the marking and construction of the nameplate that must be fulfilled to get accepted by the Department of Defense. The instructions for IUID marking of the nameplates have been mentioned by in the MIL-STD-130 N and the contractors are required to follow the instructions while manufacturing the nameplates.

The Materials

There is no specification mentioned for the materials of the UID nameplates. The contractors can provide metallic or non metallic nameplates. The DoD has allowed the use of any strong material for the construction of the nameplates. The nameplates can be of same material as the item or may be different. But, it is essential that the material of the UID nameplate shouldn’t affect the functionality of the item.

Durability

Durability is one of the significant aspects of UID nameplates. The MIL-STD-130 has made it mandatory that the UID marking of the item should be permanent for the functional lifetime of the item. The nameplates affixed to the parts or the items should remain with it for ever. That is the reason the nameplates are attached to the items with the help of screws, or quality adhesive. Once the items are tagged, they are known with their UID for the rest of their life.

Strength

The contractors are required to design the UID nameplates so that the nameplates can withstand the any environmental condition, heat and chemicals. The items are used for different function in different environmental conditions and at different temperature. Sometimes, different chemicals are used for the cleaning process of the items. The UID labels affixed to that particular item should be able to resist these things.

Compliance with MIL-STD-130

For the Department of Defense, the criteria for the UID marking and UID nameplates have been mentioned in the MIL-STD-130 N. according to the standard, the material, marking and the affixing process of the UID nameplates should not affect the item or its functionality. Even, the marking of the UID nameplates should meet the MIL-STD 130 standard. As the UID data are submitted to the UID Registry by the contractors after verification, any deviation from the standard will result in rejection.

UID Data

UID data are the important part of item identification. The data on the UID nameplates should be clear and unambiguous. There are two construct options for marking the UID data. The data on the nameplates are entered in the form of 2D datamatrix codes. The machine readable codes are decoded with the help of barcode readers. There is limitation to the size of the nameplates as well as the data.

UID nameplates are crucial for marking the items with IUID for the use of Department of Defense. However, it is important for the contractors to construct the nameplates that match the MIL-STD-130 standard.